This product, by harnessing the synergistic effect of three antibiotics, forms an exceptionally potent combination for treating infections caused by multiple bacterial agents—a common occurrence in aquatic environments.

Erythromycin is a macrolide antibiotic that reversibly binds to the 50S ribosomal subunit, inhibiting bacterial protein synthesis. It is bacteriostatic, but at higher concentrations, it may exhibit bactericidal activity. After oral administration, it is rapidly absorbed from the gastrointestinal tract and widely distributed throughout tissues, cavities, and body fluids. Its antimicrobial activity increases with pH, reaching peak efficacy at pH 8. It is primarily excreted via bile, with minor urinary elimination.

Sulfamethoxazole, like other synthetic sulfonamides, acts as an antimicrobial agent by competing with para-aminobenzoic acid (PABA) in the folic acid synthesis pathway. Since most bacteria synthesize folic acid de novo (unlike animal cells), sulfonamides selectively inhibit bacterial growth. By blocking early steps in folate synthesis, they prevent the formation of purine and thymidine precursors, essential for DNA replication. Sulfonamides alone are bacteriostatic.

Trimethoprim, a diaminopyrimidine derivative, inhibits dihydrofolate reductase, preventing the formation of tetrahydrofolate, the active form of folic acid. When combined with sulfonamides, it produces a synergistic bactericidal effect by targeting two sequential steps in the same metabolic pathway. This synergy allows for lower dosing, enhanced efficacy, and reduced toxicity.